<SOLVED> Draw_FilledBox doesn't set Alpha?

[serial]

Code:

rs2 = scene.CreateAlphaRenderSurface(128, 128)
            rs2.StartRender()
            immediate.Action_Begin2D()
            immediate.Draw_FilledBox(0, 0, 128, 128, glo.RGBA(0, 0, 0, 0))
            immediate.Action_End2D()
            rs2.EndRender()
            rs2.SaveTexture(path & project & "\" & cellname(x, z) & "\alpha.dds", CONST_TV_IMAGEFORMAT.TV_IMAGE_DXT5)
            rs2.Destroy()

I'm my world editor when I create a landscape.tvl I also create an associated alpha map. 
Currently I do that by drawing a filled box to the screen.  I want to the values to be
all 0 by default.  I've been chasing a 'bug' for a few days only to realize that Draw_FilledBox doesn't seem to draw in the alpha channel.  At least that is the only conclusion I could come up with for its behavior. 

[SylvainTV]

Well it tries to set all to 0  but it can't because alphablending and alphatesting are enabled by Default. You must disable them before rendering to the RS. (immediate.Settings* functions)

[serial]

Oh,  that fixed it :p

Thanks